This invention relates to the arrangement of touch fastener elements on a common base.
In the field of molded touch fasteners, typically a series of adjacent rows of male fastener elements, such as the molded hooks disclosed by Fischer in U.S. Pat. No. 4,974,028, engage loops or anchored fibers to form a separable closure. The male fastener elements (i.e., "hooks") extend from a common base, and have overhanging heads formed at the distal ends of elongated stems. The heads of the hooks capture and retain loops.
Molded hook fastener strips formed in a continuous process with a rotating mold roll have hooks arranged in rows running along the length of the strip, in the "machine direction" of the molding process. The heads of such hooks are generally aligned to face in the direction of the row to facilitate removal from the mold cavities of the mold roll. So aligned, molded arrays of hooks can demonstrate loop-retaining performance characteristics that are direction-dependent. For instance, a hook-and-loop closure may withstand, in some instances, a shear load in the machine direction of greater magnitude than a shear load in the cross-machine direction. This effect is partly a function of hook construction.
As used herein, these terms should be interpreted as follows: a "shear load" is a separating load applied between mating sides of a planar closure, acting within the plane of the closure; a "peel load" is a separating load applied between mating components to peel them apart, sequentially disengaging hooks (cross-machine peel typically contains an element of cross-machine shear load at the hook level); a "hook" is a male fastening element constructed to engage loops, and is not limited to a J-type shape; the "machine direction" is along the direction of extent of a row of hooks; and the "cross-machine direction" is perpendicular to the machine direction and within the plane of the closure.